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        검색결과 11

        1.
        2022.12 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 용제를 전혀 사용하지않고 UV경화가 가능한 나노 실버 페이스트를 개발하였다. 무용제(solvent-free) 타입으로 개발한 나노 실버 페이스트의 점도 및 점탄성 측정하였다. 그리고 스크린인쇄로 패턴을 인쇄한 후에 UV 경화로 전극도막을 형성시켰다. 형성된 전극도막의 전도성, 연필경도, 접착력에 대해서 평가하였다. 또한 전극 도막 을 광 소결하여 전도성을 평가하였다. 마지막으로 전극도막의 경화특성은 TGA 및 FT-IR로 평가하였다. 이러한 결 과를 정리하면 UV경화만 시켰을 경우에는 전도성, 접착력, 경화특성에 대해서는 Paste(3)이 가장 우수하였다. 그러 나 광소결 후에는 Paste(1)이 가장 우수한 전도성을 얻을수있었다. 그 이유는 10nm 실버 파우더를 사용한 것이 소 결 특성이 가장 우수했기 때문이라고 판단된다.
        4,000원
        2.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of 2-5 μm) onto a PET film, filling it with silver paste, wiping of the surface, and heatcuring the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.
        4,000원
        3.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES :Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests.METHODS:This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672.RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete.CONCLUSIONS:This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.
        4,000원
        4.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A magnetic powder, M-type barium hexaferrite (BaFe12O19), was consolidated with the spark plasma sin-tering process. Three different holding temperatures, 850℃, 875℃ and 900℃ were applied to the spark plasma sinteringprocess with the same holding times, heating rates and compaction pressure of 30 MPa. The relative density was mea-sured simultaneously with spark plasma sintering and the convergent relative density after cooling was found to be pro-portional to the holding temperature. The full relative density was obtained at 900℃ and the total sintering time wasonly 33.3 min, which was much less than the conventional furnace sintering method. The higher holding temperaturealso led to the higher saturation magnetic moment (σs) and the higher coercivity (Hc) in the vibrating sample magne-tometer measurement. The saturation magnetic moment (σs) and the coercivity (Hc) obtained at 900℃ were 56.3 emu/g and541.5 Oe for each.
        3,000원
        5.
        2011.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Ultraviolet (UV) light emitting diodes (LEDs) were grown on a patterned n-type GaN substrate (PNS) with 200 nm silicon-di-oxide (SiO2) nano pattern diameter to improve the light output efficiency of the diodes. Wet etched self assembled indium tin oxide (ITO) nano clusters serve as a dry etching mask for converting the SiO2 layer grown on the n-GaN template into SiO2 nano patterns by inductively coupled plasma etching. PNS is obtained by n-GaN regrowth on the SiO2 nano patterns and UV-LEDs were fabricated using PNS as a template. Two UV-LEDs, a reference LED without PNS and a 200 nm PNS UV-LEDs were fabricated. Scanning Electron microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Photoluminescence (PL) and Light output intensity- Input current- Voltage (L-I-V) characteristics were used to evaluate the ITO-SiO2 nanopattern surface morphology, threading dislocation propagation, PNS crystalline property, PNS optical property and UVLED device performance respectively. The light out put intensity was enhanced by 1.6times@100mA for the LED grown on PNS compared to the reference LED with out PNS.
        3,000원
        6.
        2011.05 구독 인증기관·개인회원 무료
        Pyrifluquinazon은 새로운 생물학적 활성 모형을 기초로 만들어진 화학합성 살 충제이다. 이 살충제의 작용기작은 곤충의 행동을 변형시켜 섭식을 하지 못하게 함으로서 굶어 죽게 하는 것으로 알려져 있다. 본 실험에서는 pyrifulquinazon의 완효형 제형을 만들어 복숭아혹진딧물에 대한 섭식행동과 살충효과를 검증하였 다. pyrifluquinazon nano type은 코팅할 때 사용되는 키토산 용액의 분자량과 농 도에 따라 CS 30,000 0.1%, CS 3,000 0.3%로 제조하여 완효형 제형으로 사용하 였고 원제형태의 pyrifluquinazon을 대조구로 사용하였다. 또한, EPG를 이용하여 이 약제에 대한 생물검정과 섭식행동 결과를 비교하였다. CS 30,000 0.1%를 추천 농도(50ppm)로 처리했을 때 진딧물 살충효과와 증가율은 약제 처리 초기에는 저 조하였지만 6일 후부터 점차 증가하였고, 처리 8일 후에 살충율이 가장 높았다. CS 3,000 0.3%의 경우, 처리 18일 후에 살충율이 71.7%를 나타냈고, 증가율은 -0.43 으로 효과적인 완효형 제형의 결과를 보였다. 또한, 두 가지 nano type을 각각의 농 도(25, 50, 100ppm)로 처리함에 따라, 복숭아혹진딧물에 대한 완효형 제형의 특성 과 살충효과를 관찰한 결과, CS 30,000 0.1% 타입의 생물검정 결과, 다른 농도에 서 보다 100ppm으로 처리한 경우 약제 처리 후 모든 일차에서 가장 효과적으로 증 가율 저해가 관찰되었고, CS 3,000 0.3%를 100ppm으로 처리한 경우 약제 처리 18일 후에 살충율이 68.3%로 가장 높았다. 25, 50ppm의 농도로 희석된 2가지 nano 타입과 원제 형태의 제형에 대한 복숭아혹진딧물의 생물검정과 섭식행동을 비교하기 위해서 EPG를 수행한 결과, 25, 50ppm 모두 원제 형태의 제형의 경우 섭식 억제 효과가 약제 처리 2일 후에 가장 좋았지만, CS 30,000 0.1%는 25ppm에 서 처리 8일 후, 50ppm에서 처리 14일 후, CS 3,000 0.3%의 경우 25ppm에서 처 리 28일 후, 50ppm에서 처리 14일 후에 섭식억제 효과가 가장 우수하였다. 또한, 25ppm의 CS 3,000 0.3%에서 처리 12일부터 30일 까지, 50ppm에서는 처리 14일 부터 30일까지 reaction time이 관찰되어 CS 3,000 0.3%가 가장 효과적인 완효형 제형의 특징을 나타내었다.
        7.
        2010.10 구독 인증기관·개인회원 무료
        Pyrifluquinazon, as a quinazinalone chemical group, based on a new mode of biological activity. It is reported that mode of action is modifies insect behavior, rapidly stopping feeding such that insects starve to death. Time-release feature and mortality effect on M. persicae using different pyrifluquinazon nano type and non-nano type were compared. Pyrifluquinazon nano type was formulated with different molecular weight and density of used chitosan (CS 30000 0.1% and CS 3000 0.3%). In the CS 30,000 0.1%, the mortality was weakly occurred at early time, but steadily increased after 4days. Finally, we confirmed more than 70% mortality as a peak at 16days. In CS 3000 0.3%, the mortality showed about 70% until 18days as a effective controlled release. Also, We examine time-release feature and mortality effect on M. persicae according to the different pyrifluquinazon nano type(CS 30000 0.1% and CS 3000 0.3%) of concentrations. The CS 30000 0.1% bioassay results of different concentration were showed that the highest concentration(100ppm) was measured better mortality than other concentration at 0 day, but cannot confirm different effect about dissimilar concentration. However, increasing rates of M. persicae were low as treatment concentrate was high. In CS 3000 0.3% 100ppm concentration bioassay result, aphid mortality reached peak at 24 days and increasing rate also low. Additionally, for the comparing of bioassay and feeding behavior of M. persicae against pyrifluquinazon nano types and non-nano type, EPG technique was carried out. In case of non nano type, feeding inhibition efficacy was showed during 4 days after treatment, but appeared similar level with control after 10days. In CS 3000 0.3% 50ppm, residual efficacy was specially showed until 28days after treatment whereas treatments with CS 30000 0.1% were similar to the control after 22days. These result show that the change of feedinng behavior and motrality of M. persicae is correlated with the change of nano type or non nano type of pyrifluquinazon.
        8.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Homogenous silica-coated samples with controlled silica thickness were synthesized by the reverse microemulsion method. First, 7 nm size cobalt ferrite nanoparticles were prepared by thermal decomposition methods. Hydrophobic cobalt ferrites were coated with controlled using polyoxyethylene(5)nonylphenylether (Igepal) as a surfactant, and tetraethyl orthosilicate (TEOS). The well controlled thickness of the silica shell was found to depend on the reaction time and the amount of surfactant used during production. Thick shell was prepared by increasing reaction time and small amount of surfactant.
        4,000원
        9.
        2001.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        /TiN nano/nano-type composites were successfully fabricated by the combination of a mechano-chemical grinding (MCG) method and a short time sintering process, and their wear resistance was evaluated. Powder mixtures of and Ti were prepared using mechano-chemical grinding process and the resulting nanocomposite powder mixtures were consolidated using pulsed electric current sintering (PECS). TEM observation showed that the nano/nano-type composites consisted of homogeneous and very fine matrix grains with the size less than 100 nm. The obtained -based nano/nano-type showed high wear resistance and electric discharge machinability.
        3,000원
        10.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 미백제인 RS White를 함유한 O/W 나노에멀젼의 형성 가능성을 유화제 종류별로 실험하 였다. 친수성계면활성제로 Tween 80, 60, HCO 60 및 40과 친유성 계면활성제로 Span 80을 사용한 시스템 에서는 적정한 농도에서 나노에멀젼이 형성되었으나 Myrj 52, Montanov L 및 Tegocare 450과 Span 80을 사용한 시스템에서는 형성되지 않았다. 형성된 나노에멀젼은 입자의 직경이 100 nm 미만의 반투명 외관을 보 였으며 시간 경과에 따른 안정성 평가에서도 안정성을 유지하였다. 이들의 경피흡수 정도를 마크로에멀젼과 비 교한 결과 24 h 동안 피부 투과량은 나노에멀젼은 70.84 μg/cm2, O/W 마크로에멀젼은 28.97 μg/cm2으로 나 타났다. 따라서, 본 연구는 RS White 미백제를 함유한 안정한 나노에멀젼이 기능성 소재의 효율적인 피부 전달 체로서 응용 가능성이 있음을 시사한다.